startup issues

[misterRollsRoycer]

Hey everyone. When starting my car cold (98 lesabre 3.8L), rpm goes up fine but wants to keep dropping below 1200 mark, does, and car stays off. Voltage at same time says below 12 and won't climb. Then try again and give some gas on startup and rpm's climb up to correct mark, voltage climbs to correct mark as well. After bunch more startups later on that day, and little gas each time, rpm's hold well- 1200 at idle. After that cold start also, even if car stays on, rpm goes just below 1000 and battery at exactly 12 volts. For about minute or so. Feels and sounds like car is off but it is somehow just operable enough. After that minute though, stays at steady 1200 rpm and voltage at just over 14. It seems acceleration pedal always needed to get rpm's in correct zone and battery as well. Shouldn't normally have to give gas at startup should I? Even though I think that's been a habitual thing I've done anyway. Just never thought about it. Have fuel pressure tester and will try. Possible fuel pressure regulator problem? MAF sensor? (was told to tap on it to see if rpm's shifted up or down while car in idle). Spark plugs? IACV? Throttle position sensor? Any ideas? It seems like if anything it's directly associated with voltage- fuel consumption and voltage. Thanks for any help guys.

 

[Spriteman]

If you're good with a multimeter check out this website - http://easyautodiagnostics.com/gm/3.8L/index-of-articles-1

It gives many good tests and questions & answer of how to proceed based on the last test.

To me it sounds like the TPS - if the TPS is not varying the voltage from 0 - 5 volts then the PCM won't be able to adjust the amount of fuel.

But, use the tests and it will narrow down the possibilities.